Experimental investigation on the formation behavior for three-layer metal sheets under laser high speed flexible micro-forming

Laser high speed flexible micro-forming (LHSFF) process has been applied to the formation of metal sheets due to its unique advantages compared to conventional micro forming processes. The materials investigated in LHSFF were all single-layer metal sheets so far. However, new materials have been developed to replace single-layer metal sheets in some industry occasions because of their superior properties. This paper investigated a new process that employed LHSFF on the formation of multilayer metal sheets. The feasibility of this new process for three-layer Ni/Cu/Ni metal sheets was verified firstly. Some results could be obtained from the experiments. Surface roughening happened in formed components, and surface quality became worse with laser energy increasing. As thickness of soft punch increased, the forming depth of Ni/Cu/Ni metal sheets decreased under LHSFF. The thickness reduction and the amplification of micro-hardness of the external layer were larger than those of the middle layer, and those of the middle layer were larger than in the internal layer. Unlike conventional forming processes, the formation of Ni/Cu/Ni metal sheets did not suffer from delamination failure any more under LHSFF.